Transformer station grounding network corrosion diagnosis method based on magnetic field inverse problem solving

Abstract

The invention relates to a transformer station grounding network corrosion diagnosis method based on magnetic field inverse problem solving, which comprises the following steps: calculating a theoretical ground surface magnetic induction strength of a transformer station grounding network according to a number calculation method; inputting an AC excitation current into the transformer station grounding network, sensing a ground surface magnetic field by a detecting coil along the upper part of the grounding network, and acquiring an induction voltage signal by a data acquisition device; calculating magnetic induction strengths at n measuring points according to the acquired induction voltage signal; according to the magnetic induction strengths at the n measuring points, calculating the axial current of n conduction segments of the grounding network by means of a Tikhonov regularization algorithm; obtaining an actual calculation result for the ground surface magnetic induction strength of the grounding network; and comparing the actual ground surface magnetic induction strength of the grounding network with the ground surface magnetic induction strength which is obtained through calculation under a normal working condition. Compared with the prior art, the transformer station grounding network corrosion diagnosis method has advantages such as improving operation reliability of the transformer station grounding network.

Description

technical field [0001] The invention relates to the technical field of power grid detection, in particular to a method for diagnosing corrosion of a substation grounding grid based on solving a magnetic field inverse problem. Background technique [0002] The grounding grid is an important guarantee for the safe operation of the substation, and its reliability has a great impact on the safe and stable operation of the power system. Since most domestic substation grounding grids are made of flat steel, round steel and other steel materials, and they are buried underground for a long time, they will inevitably be electrochemically corroded by the soil, which will cause the grounding grid equalizing conductor to corrode or even break, and the grounding down conductor Smaller cross-section, poor contact between grounding bodies, etc. These faults will greatly reduce the performance of the grounding grid, seriously endangering the safety of workers and equipment in the substatio...

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Problems solved by technology

[0003] At present, there are mainly three methods for detecting grounding grid corrosion faults: one is based on circuit theory, and realizes fault diagnosis of grounding grids by establishing fault diagnosis equations and combining corresponding optimization algorithms. accuracy, and it is difficult to obtain identification and diagnosis by this method when there are only minor faults in the grounding network

The second is based on the electric field theory, by injecting excitation current into the grounding grid to detect the distribution of the ground surface potential, so as to diagnose the fault of the grounding grid, but this method requires more measuring points and a large workload, and may cause Misjudgment or missed judgment of the fault point

The third is based on the electromagnetic field theory, by injecting excitation current into the grounding grid to detect the magnetic induction intensity of the ground surface, and then diagnose the fault of the grounding grid according to the distribution characteristics of the magnetic induction intensity. Grounding grid, but subject to the site conditions of the substation in actual application, it is difficult to accurately measure the magnetic induction intensity of all measuring points, and there is a problem of heavy workload for large-scale grounding grids

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